Nearly 639 million people in the country do not have access to essential medicines even though the pharmaceutical industry is one of the best performing sectors in Indian business and medicines manufactured in India are exported to 200 countries. Stating this here on Thursday, Dr. Amit Sengupta, joint convener of Jan Swasthya Abhiyan, one of the organisers of a two-day national workshop that begins here this Friday, regretted that 50 per cent to 80 per cent of the people do not have access to essential medicines.